BioMedical Admissions Test (BMAT) Practice Test 2026 - Free BMAT Practice Questions and Study Guide

Neurotransmitter molecules are released into the synaptic cleft through a process known as exocytosis. This process involves the fusion of synaptic vesicles, which contain neurotransmitters, with the presynaptic membrane in response to an influx of calcium ions. When an action potential arrives at the axon terminal, it triggers voltage-gated calcium channels to open, allowing calcium ions to enter the neuron. The increase in intracellular calcium concentration induces the synaptic vesicles to dock and fuse with the membrane, thereby releasing neurotransmitters into the synaptic cleft.

This mechanism is vital for the communication between neurons, as neurotransmitters then bind to receptors on the postsynaptic membrane, leading to various physiological responses. The specificity of exocytosis ensures that neurotransmitters are released in a controlled manner, which is crucial for proper neural signaling.

While active transport, passive diffusion, and diffusion are relevant concepts in cell biology, they do not accurately describe the process of neurotransmitter release. Active transport typically refers to the movement of ions or molecules against their concentration gradient, requiring energy. Passive diffusion involves the movement of molecules down their concentration gradient without the need for energy. While neurotransmitter molecules may later diffuse across the synaptic cleft to